The interactive television set may be an analogue television set with a Controller (a decoder, or a ‘set-top box’, for example) or an integrated digital Television set, both of which will be referred to as ‘a dTV’ herein. The messaging service may be, for example, GSM Short Message Service (SMS) or IP-based Instant Messaging where a telephone number is associated with the sender. The messages can also contain images and video clips, sent via Multimedia Messaging services, using WAP or 3G and similar technologies.